Randall-style intake for the coldside?

[goberserk]

If you're not familar with the Randall cowl intake duct, FM sells it here. (http://flyinmiata.com/index.php?deptid=1598&parentid=0&stocknumber=05-27000)

Follow the link to the dyno chart too.

Anyway, my idea is obvious now. Why not try using a Randall-Cowl-style intake system for the coldside? Instead of routing down behind the blower and wrapping forward again. Just head straight back for the firewall. It doesn't look like there is too much in the way of cutting a hole there. Some ducting will need to be fabbed to surround the cylindrical filter so it only sees air coming from the hood/windshield seam. But it might have some promise . . .

Here's a question though that just crossed my mind: how does the super regulate its output pressure? Is it only via the pulley? Is there no software control as in some turbo setups with an electrically controlled waste-gate?

As your intake (to the super) pressure goes up (and you don't change anything else) do you get more boost with the same parasitic losses or the same output pressure with less robbed power? or a little of both? I guess if you got more boost (and didn't want it for whatever reason) you could choose a different pulley to bring it back down - and of course the lower boost pulley will rob less power from the engine which will leave you with more power than if you had lower intake pressures and the higher power pulley.

-Jake

[chuckerants]

On my hotside, I've also considered going straight into and through the firewall and have the filter below the windshield.

[Zoomster]

I just finished up doing a DIY CIA Cowl Intake on my '95 Coldside and although I haven't had it on a dyno my "seat if the pants dyno" tells me there's a difference or maybe it's the much more prevalent "open for business purr, growl and scream. I used a K&N "cone style" air filter located within the driver's cowl area. The reason for going clear back across the engine bay and then through the cowl was there is no room to go through the cowl on the passenger side. Between the ABS, Tom's vacuum manifold and a couple more goodies the passenger cowl area was off limits. The connections amd plumbing were made up from various spare stuff laying 'round the garage and a piece of 3" aluminized exhaust made up by a local exhaust shop. When I get back around the car in a couple of days I will get you a part number for the filter. I had to go over the cam/valve cover which I wasn't crazy about but it doesn't look all that bad after insulating the flattened 3" section of aluminized and using some SS tie wire to temp. securing it to the shock tower brace.

[Tom @ Fast Forward]

I have thought about the same thing on several occasions. I think somebody with a coldside has run the hose into the cowl and put the filter there. Only thing that stops me is that I need to build/sell a kit that will work for all buyers. A lot of them don't even like drilling the couple screw holes to mount the IAC and VDB. Trying toconvince them to bore a 3" diameter hole in the cowl would not be practical. I pulled the full race engine and sold it at a loss so I could be testing on a stock engine like my customers.

IOW, as much as I like the idea of cowl intake, I can't lose sight of my core customers. On the other hand, you could do it. I'd love to see it done. I have tested the intake in a couple different places under the hood on the road while monitoring the intake air temperature in the manifold. It appears to have no effect. I have also tested it on the dyno with the hood open and the intake up in the air away from the engine. No great effect there either. The blower adds about 180F to the ambient air and the E-Cool knocks it right back down. I found the real culprit to ping is the engine heat itself. At a certain point, the engine is just too hot. Best thing is really good cooling with the fans sealed to the radiator. That appears to do more good than the cold air intake for heat/Ping. HP wise, the colder the air the more oxygen and the more HP you can make but a one size change to the pulley more than compensates for the loss of O2.

I would love to have mine in the cowl simply because I love the scream of the Eaton and where the intake is now, you barely hear it.

[Steve]

I thought about doing this for the FFSC in my NA but the wiper mechansim is in the way. One possibility would be to remove the windshield washer bottle and build an airbox in that space that breathes from the cowl area.

I've never used my washer bottle, but might need wipers someday.

[Wayne-n-Fla]

"MATHRIPS" built one, there may be pic's posted ?

[Gord96BRG]

There's a current thread on Miata.net discussing this - here:
http://forum.miata.net/vb/showthread.php?t=198810

Mathrips posted a picture of his cowl-entry intake there. I went the other direction, and put the filter in the lower front of the passenger side wheel well. It gets a straight shot of cold air from the duct in the OEM air dam on my 96. I was measuring air temp at the filter of ~40C (~105F) stabilized after driving a while with the filter in the original location below the steering rack/antisway bar, with ambient temps of ~22C (~70F). With the filter in the wheel well, filter air temps are strictly ambient. Pics are in that Miata.net thread.

Regards,
Gordon

[Steve]

Mathrips idea is exactly what I was thinking.

My first thought was to do something like Gordon's, but in my car that's where my remote oil filter is going so there may be some arguments over space. With the hose still running alongside the engine I wonder how much the air temp will increase before it gets to the TB? Maybe not much at WOT because the air is moving through so quickly.

[Gord96BRG]

I see nobody else is too impressed with my air filter relocation and splash shield, and you all are too polite to say anything unkind about it! :P Hey, at least Corky Bell liked it... OK, didn't say anything bad about it in public! :wink:

[99mx5]

I liked your idea Gordon. I'll have to see how much space is on the NB.

[Tom @ Fast Forward]

I'm still trying to convince my wife that a hole in the hood with a scoop and filter would really look great. I have always been a fan of hood scoops. However, when I mock one up, I have a hard time seeing over it. And it would block her view even worse. Sadly, she gets the last word on stuff like that

[raceskier]

Gordon,

I like it too. I'm just not sure about the routing and space available for a NB as opposed to a NA. I was looking at Daz's oil cooler mounting detail, where he used the same area. It looks quite a bit different from you car. I just need to take the time to see how everything will fit.

[goberserk]

Instead of an outward/external (having a hard time with the right word there) scoop how about an 'internal scoop'; like a NACA duct. It would be similar to the kind available on a headlight cover.

http://www.revlimiter.net/mods/pix/sc_box7.jpg

Althought the hood isn't the optimal place for one, you could fit a larger one than on the headlight cover assuming there is enough depth under the hood for it.

That pic came from here. (http://www.revlimiter.net/mods/coldside_isolator.html)

[FormerDatsun510Man]

Neat ideas. How about a shaker style mini hood scoop? Perhaps that and additionally vents cut in the hood above the supercharger to aid in cooling it down as much as possible.

Bill